In an automotive engine, the idling speed tends to vary over a substantial range depending upon ambient conditions and engine load conditions, especially in an engine provided with fuel injection. When the engine throttle is in the idling position the induction passage from the air cleaner to the intake manifold is throttled to a fixed opening. Accordingly, a change in engine load or ambient conditions which tend to reduce engine speed also have the effect of producing an excessively rich air/fuel mixture. A change in engine load or ambient conditions which tends to increase engine idling speed results in an excessively lean air/fuel mixture. It is desirable to automatically change the flow of intake air in response to such engine load or ambient condition changes so that the engine speed can remain substantially constant. It is an objective of this invention to provide a control system for maintaining engine idling speed substantially constant despite variations in engine load conditions and certain ambient operating conditions.